Binaural and method of making the same

ABSTRACT

A stethoscope method of making a stethoscope binaural from an elongated resilient tubular member preferably having a symmetrical cross section comprising sliding a tubular T-shaped yoke onto the tubular member, then bending and setting the tubular member and T-shaped yoke in a jig into a substantially symmetrical U-shaped having two legs and a bight with one leg and the adjacent portion of the bight lying substantially in one plane and the other leg in its adjacent portion of the bight lying in a second plane intersecting the first at an angle of 150* . A hole is formed in the tubular member through the base of the T-shaped yoke and a tubular retaining pin is inserted. A tube is then connected to the tubular pin of the binaural. In a preferred structure of the binaural there is provided a tubular homogenous mass of plastic having a cross-sectional configuration in which the thickness of the tubular wall is greater in a direction normal to the major plane of the stethoscope and in which the binaural is provided with a pair of legs and an interconnecting bight section continuous and integral with one another with the legs resiliently urged toward a normal untensioned position by the characteristics of the plastic material. A generally T-shaped member having a channel in the crossmember of the T and a tubular stem engages the bight of the binaural and provides means for connecting a flexible tube in turn connected to a chest piece.

United States Patent [72] Inventors David Littmann;

} Gustav F. Machlup, both of Belmont, Mass. [21] Appl. No. 742,404 [22]Filed July 3, 1968 [45] Patented Nov. 9, 1971 [73] Assignee MinnesotaMining and Manufacturing p y Village of Maplewood, Minn.Continuation-impart of application Ser. No. 643,728, June 5, 1967,'nowabandoned.

[54] BINAURAL AND METHOD OF MAKING THE SAME 22 Claims, 34 Drawing Figs.

[52] U.S. Cl 181/24 [51] Int. Cl. A61b 7/02 [50] Field oISearch181/24,23; 179/1; 138/177; 11/11 [56] References Cited UNITED STATESPATENTS 8,591 12/1851 Marsh 181/24 1,585,407 5/1926 Morin 181/242,261,912 11/1941 Buente 138/177 2,458,884 1/ 1949 Volkmann 128/1522,498,960 2/1950 Mullin 179/156 3,303,902 2/1967 Knott 181/23 3,437,1724/1969 Allen 181/24 3,346,069 10/1967 Speelman 181/24 FOREIGN PATENTS530.297 12/1940 Great Britain. v. l38/D1G. 11

Primary Examiner-Stephen J. Tomsky Attorney-Wolf. Greenfield & SacksABSTRACT: A stethoscope method of making a stethoscope binaural from anelongated resilient tubular member preferably having a symmetrical crosssection comprising sliding a tubular T-shaped yoke onto the tubularmember, then bending and setting the tubular member and T-shaped yoke ina jig into a substantially symmetrical U-shaped having two legs and abight with one leg and the adjacent portion of the bight lyingsubstantially in one plane and the other leg in its adjacent portion ofthe bight lying in a second plane intersecting the first at an angle of150". A hole is formed in the tubular member through the base of theT-shaped yoke and a tubular retaining pin is inserted. A tube is thenconnected to the tubular pin of the binaural. in a preferred structureof the binaural there is provided a tubular homogenous mass of plastichaving a cross-sectional configuration in which the thickness of thetubular wall is greater in a direction normal to the major plane of thestethoscope and in which the binaural is provided with a pair of legsand an interconnecting bight section continuous and integral with oneanother with the legs resiliently urged toward a normal untensionedposition by the characteristics of the plastic material. A generallyT-shaped member having a channel in the crossmember of the T and atubular stem engages the bight of the binaural and provides means forconnecting a flexible tube in turn connected to a chest piece.

PATENTEDuuv s I97| 3,618,697

sum 1 OF 6 WWW Y I a? 1 v F5570 M/VENIOR BINAURAL AND METHOD OF MAKINGTHE SAME The present application is a continuation in part ofapplication Ser. No. 643,728 filed June 5, 1967. now abandoned.

BACKGROUND OF THE INVENTION The present invention relates generally to abinaural construction designed for use with medical stethoscopes.

Medical stethoscopes presently commercially available ordinarily areprecision built instruments that are relatively expensive tomanufacture. These expensive stethoscopes, however, are not adapted foraseptic procedures presently desired in treatment of most contagiousdiseases. Although doctors are quite careful to dispose of or sterilizemouth depressors, thermometers and other instruments when treatingsuccessive patients, they nevertheless ordinarily fail to use the samecareful procedures with their stethoscope. This failure to maintainsterile procedures with respect to a stethoscope if probably due to thefact that this instrument is not disposable and cannot be autoclavedeasily. Because of these factors there is a substantial need for amedical stethoscope which is either autoclavable or is relativelyinexpensive to manufacture and consequently may be disposed of after asingle use. Although there have been efforts to make plastic binauralswhich are inexpensive these methods are not satisfactory for severalreasons. First, some methods result in binaurals which are not capableof standing up under the considerable abuse to which they are normallysubjected. Further, the methods practiced in manufacturing some of thesedevices are not particularly adapted for mass production purposes. Inaddition many binaurals made by earlier methods do not fit properly on awearer's head and have a tendency to torque when worn. This latterproblem is a difficulty of considerable importance for it all buteliminates the utility of plastic binaurals of the type described forany purpose other than toys. Torquing is intended to refer to thetendency of a binaural having legs and a bight formed of a single lengthof plastic tubing to twist about a vertical axis through the center ofthe bight in opposite directions when worn as a normal binaural.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a disposable binaural design for use in a medical stethoscopewhich is so inexpensive to manufacture that it may be disposed of aftera single use in most ordinary medical practices. It is also an object ofthe present invention to provide a relatively inexpensive binaural foruse as a medical stethoscope which is lightweight, easy to handle, andrugged. A further object of this invention is to provide a binaural foruse in a stethoscope made entirely of plastic, and therefore notchilling, in which the bight of the binaural is provided with areinforcing yoke on its outer surface having a generally T-shapedconfiguration with the yoke functioning in part to provide controlledflexibility and resiliency. A further object of the present invention isto provide a binaural having ear plugs attached to the ear tube ends ofthe binaural with the ear tubes formed of a flexible or deformablematerial designed to be flexed to readily conform with the shape of thewearers ear canal.

It is also an object of the present invention to provide an improvedmeans and method of fabricating in commercial quantities binaurals forstethoscopes from tubing, preferably .of plastic. A further object ofthe present invention is to provide a method of fabricating binauralsespecially designed for stethoscope use which are not likely to torqueand which will withstand considerable abuse without leaking or otherwisebecoming defective. A still further object of the present invention isto provide an improved binaural construction which is particularlyadapted for a variety of uses including and preferably; stethoscopes.One further object of the present inventionis to provide a unique meansand method of shaping a binaural for astethoscope to the particularshape found most appropriate for such binaurals. A still further objectand advantage of the present invention is to provide a means and methodof securely attaching a stem to the bight of a stethoscope binaural.

In one embodiment of the present invention there is provided astethoscope binaural construction formed of an elongated tubularhomogenous mass having a cross-sectional configuration with thecross-sectional diameter in one direction greater than a correspondingcross-sectional diameter normal thereto. The binaural is provided with apair of legs and an interconnecting bight section continuous andintegral with one another. The legs are resiliently maintained in or areurged toward a normal untensioned position against deforming forces atleast in part by the characteristics of the mass forming the binauraland, if desired, to some extent by a reinforcing yoke having a T-shapein which the crossmember of the T engages the bight of the binaural.

In a modified form of the invention the legs of the binaural areintegrally connected to a resilient yoke which functions in part as aspring member to maintain the legs of the binaural in generally aU-shaped configuration. Further features of the present inventionprovide improved yoke means for securing the binaural to the stem of thestethoscope.

In the preferred method of the present invention a T-shaped yoke isthreaded onto an elongated resilient tubular member. The member is thenbent and set into a U-shaped configuration having two legs and a bightwith one leg and an adjacent portion of the bight lying substantially inone plane and the other leg and its adjacent portion of the bight lyingin a second plane intersecting the first preferably at an angle ofsubstantially 15. A hole is formed in the bight aligned with the stem ofthe yoke and a retaining pin is then forced through the stem and intothe hole. In a modification of the method the U- shaped tubular membermay be reformed with its legs in a crossover position. And while in thisposition a yoke is formed on the bight portion of a resilient materialcapable of normally retaining the legs in this crossover position. Theyoke is formed with two legs molded over the bight and a stem having anopening extending longitudinally through it extending away from thecenter portion of the bight with the opening in the stem in fluidcommunication with the opening of the legs.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantagesof the present invention will be more clearly understood when consideredin conjunction with the accompanying drawings in which:

FIG. 1 is a partially cross-sectioned elevation of a binaural embodyingthe invention;

FIG. 2 is a top plan view of the binaural illustrated in FIG. 1;

FIG. 3 is a fragmentary cross-sectional detail of the ear tube and earplug forming a portion of the invention;

FIG. 4 is an end view of the earplug illustrated in FIG. 3;

FIG. 5 is a cross-sectional view taken substantially along line 5-5 ofFIG. 1;

FIG. 6 is a cross-sectional view taken substantially along the line 6-6of FIG. 1;

FIG. 7 is a cross-sectional view taken substantially along line 77ofFIG. 6;

FIG. 8 is a cross-sectional view taken along the line 8-8 of FIG. 1;

FIG. 9 is a cross-sectional view of a modification of a binauralillustrated in FIG. 1 taken substantially along a correspond ing line tothat illustrated at 8-8 in FIG. 1;

FIG. 10 is a cross-sectional view of a still further modification takenalong lines corresponding to line 8-8 of FIG. 1;

FIG. 11 is a plan view of a binaural in fragmentary cross sectionillustrating a modification of the invention;

FIG. 12 is a plan elevational view of a binaural illustrating apreferred embodiment of the invention;

FIG. 13 is a cross-sectional view taken along line 13-13 of FIG. 12;

FIG. 14 is a cross-sectional view taken along the line 14-14 of FIG. 12;

FIG. 15 is a bottom view of the embodiment illustrated in FIG. 12;

FIG. 16 is a cross-sectional detail of an earplug used in a preferredembodiment of the invention;

FIG. 17 is a bottom view of the earplug shown in FIG. 16;

FIG. 18 is a perspective view of a jig used in making the binaurals ofthe present invention in accordance with the preferred form of theinvention;

FIG. 19 is a component of a yoke used in a modification of theinvention;

FIG. 20 is a cross-sectional view taken along the line 20-20 of FIG. 19;

FIG. 21 is a plan view ofthe mating halfof FIG. 19;

FIG. 22 is a cross-sectional detail in an enlarged scale taken alongline 22-22 of FIG. 21;

FIG. 23 is a cross-sectional detail taken in an enlarged scale alongline 23-23 of FIG. 19;

FIG. 24 is a plan view of one half of mating components used in amodification of the invention and FIGS. 24a to 241 are respectivelycross-sectional details taken along the corresponding lines 24a to 24iof FIG. 24 and FIG. 24x is a crosssectional enlargement of the portionof FIG. 24 shown by the dotted circle 24x.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 there isillustrated a binaural comprised of an elongated tubular homogenous massof plastic material. Preferably the entire binaural construction hereindescribed is made of a synthetic organic plastic material with theplastic material normally being nondeformable but flexible andresilient. A variety of suitable plastics may be used provided theyimpart the desired physical characteristics to the binaural. A suitableclass of plastics includes, for example, plastics in the polypropylenefamily. The binaural consists primarily of legs 1 and 2 with acontinuous and interconnecting bight section 3. The legs 1 and 2 andbight 3 are preferably formed of an extruded polypropylene tubing whichis bent by known means on of heat into the shape generally describedherein. In this arrangement the free ends of the legs 1 and 2 are bentrespectively into ear tubes 4A and 4. The ear tubes 4A and 4 extendgenerally at a angle from the major plane of the stethoscope. The majorplane of the stethoscope is defined for purposes of this disclosure asthe plane of a flat surface upon which the stethoscope rests when laidon the surface in the position illustrated in FIG. 1 relevant to thepaper of the drawmg.

The tubular cross section of the preferred embodiment is bestillustrated in FIG. 8. In this arrangement, as viewed in FIG. 8, thevertical minor axis is shorter than the horizontal major axis with thehole 6 being circular. The greater amounts of mass formed in the wall ofthe tubular cross section, as illustrated at 7 and 8, extend the entirelength of the legs and bight portion on the sides thereof and formintegral and homogenous springlike members which normally tension orurge the legs toward a normal position, as illustrated in FIG. 1,against DEFORMING forces. Thus in a normal position the legs 1 and 2cross each other at 10. When deformed so that the ear tubes 4A and 4 canbe fitted into the wearer's ear, the legs 1 and 2 are spread apart toform an open U which, as a consequence of the characteristics of theplastic material used, provides and maintains a force which holds theear tubes on the wearer's head during normal usage.

In the preferred cross-sectional embodiment illustrated in FIG. 8, awide variety of cross-sectional configurations and dimensions may beused. A typical cross-sectional arrangement provides an inner dimensionin the order of 0. I63 inches with a maximum outer diameter of 0.3 l8inches and a minimum outer diameter of 0. l 90 inches. The hole oropening 6 through the tubular mass is preferably continuous along itsentire length except for an opening 10' centrally located in the bight 3with this opening directed outwardly in a direction opposite to thedirection of the legs 1 and 2. A yoke or T-shaped member 11 having acrossmember l2 and stem 13 is secured to the bight 3 of the binaural.The crossmember 12 is channeled or grooved as best illustrated in FIG.5, with sidewalls l5 and 16 of the channel extending more than about thebight 3 so as to provide a firm interengaging grip as illustrated inFIG. 5. The ends of this crossmeber are tapered in thickness from theinner ends 17, as illustrated in FIG. 7, to the outer ends 18. Thecrossmember 12 is preferably flared or curved to conform with the bight3, as is illustrated in FIGS. 1 and 7. The stem of the yoke or T-shapedmember is tubular with the tubular opening 20 extending from the bottomof the stem through the bottom of the cross member 12 and in alignmentwith the opening 10.

In fabricating this binaural the yoke or T-shaped member 11 isinterengaged with the bight 3 before the hole 10' is formed in thebight. After the yoke is secured on the bight, as illustrated in FIG. 1,the hole 10' is drilled through the bight by a drill projecting upwardlythrough the stem 13.

The yoke may be suitably welded to the binaural tubing by anysatisfactory bonding method such as R.F. induction heatmg.

The ear tubes 4A and 4 have secured at their extreme ends plugs 30. Eachplug 30, which is best illustrated in FIG. 3, is formed of a resilientdeformable thin wall tubular member. This plug may be formed of anysuitable material such for example as polyethylene or rubber. Thethickness of this tubular member forming the plugs 30 may vary butpreferably is in the order of 0.010 to 0.015 inches. The plug is formedwith an inner cylindrical segment 31 confonning and frictionallyengaging the free end of the ear tube. Continuous with the innercylindrical segment 31 is an outer frustoconic segment 33 with thesegment 33 connected at its narrower end 34 to the outermost end of theinner cylindrical segment. The other end 35 of the frustoconic segmentis free and spaced from the tubular segment. The tapered or frustoconicshape 35 is easily deformed to conform with the wearer's ears withoutany discomfort.

The binaural legs 1 and 2 and bight 3 may be extruded in a variety ofshapes. Such shapes are illustrated in FIGS. 9 and 10. Thus, forexample, in FIG. 9 the cross-sectional shape of FIG. 8 may be modifiedby providing side bulges 41 and 42 which are presumed to function muchin the fashion as a spring to normally maintain the binaural in theshape of FIG. I when not under stress. FIG. 10 illustrates a furthermodification in which rectangular shapes are used to maintain a greatermass in one cross-sectional direction than another to effect aspringlike action on the binaural. In this arrangement there is agreater mass on sides 43 and 44 which are also at the sides of thebinaural.

Referring to FIG. 11 there is illustrated an arrangement in which thebinaural 40 is formed with legs 41 and 42 integrally connected by abight portion 43. These legs 41 and 42 and the integral bight 43 may beformed of the same material and with the same cross-sectionalconfiguration as the embodiment illustrated in FIG. 1. The free ends,the legs 41 and 42 extend preferably in planes which lie in a 15 anglewith respect to the major plane in the stethoscope. The ends of the legs41 and 42 are provided with ear plugs 44 and 45 which may be similar tothose hereafter or previously described. The integral legs 41, 42 andbight 43 are preferably shaped and set in the position illustrated inFIG. 11. A yoke generally illustrated at 45 is then formed about thebight 43 and adjacent ends of the legs 41 and 42. The yoke 45 isintegrally formed with legs 46 and 47 interconnected by a bight portion48. A stem 49 extends symmetrically downwardly from the bight 48. Anopening 48A through the legs 46, 47 and bight 48 is preferably shapedand dimensioned to conform with and is engaged by the outer dimensionsof the legs 41, 42 and bight 43. The opening through these legs 46, 47and bight 48 freely communicates with the opening 488 through the stem49. The yoke 45 is positioned snugly over the bight 43 and adjacentportions of legs 41 and 42 with an opening 50 in the bight 43 alignedwith the opening in stem 49 to provide free fluid communication betweenthe legs 41, 42 and internal portion of the stem 49.

The wall thickness of the legs 46 and 47 preferably should taper from athickest portion adjacent the stem 49 to the thinnest portion at thefree ends of legs 46 and 47. A gradual tapering 'of a thickness from0.050 to 0.010 inches is satisfactory. This yoke 45 may be made of avariety of materials including for example,-the same type of materialsof which the legs 41, 42 are formed. By tapering the legs 46 and 47 ofthe yoke as indicated, a greater spring action may be effected on thelegs 41 and 42.

Referring now to FIGS. 12-17 inclusive there is illustrated a preferredembodiment of the present invention. In this arrangement the binaural ispreferably formed with an elongated tubular member 51 shape to providelegs 52 and 53 integrally connected by a bight 54. The tubular member 51is formed, preferably, with a wall having a nonuniform thickness. In thepreferred embodiment the wall thickness which is illustrated in FIG. 14has a major axis 56 and a minor axis 57 extending at right angles to oneanother. The major axis preferably should be in the order of magnitudeof 50 to 100 percent greater than the minor axis and in a preferredembodiment the major axis 56 should have a length of 0.320 inches andthe minor axis 0.190 inches. The hole or aperture 58 that extendslongitudinally through the tubular member 51 is preferably circular incross section and has a diameter in the order of magnitude of about 30to 40 percent ofthe major axis. In the specific embodiment the diameter58 is in the order of magnitude of 0.125 inches.

The ear tubes 52 and 53 extend generally at a angle from the major planeof the stethoscope. The major plane of the stethoscope is defined forpurposes of FIG. 12 as a plane of a flat surface upon which thestethoscope rests when it is laid on the surface with the side 60 (FIG.15) touching the surface. In this position the legs 52 and 53 will touchthe surface in the areas generally illustrated at 61 and the bightportion 54 as well as the free ends 63 of the legs 52 and 53 will beremote from the surface. The main axis 56 is flared outwardly inopposing portions of the legs 52 and 53 as viewed in FIG. 12 lookingdownwardly at the binaural when it is resting on its major plane.

The yoke 65 is preferably formed of an injection molded relatively rigidplastic having sufficient structural rigidity to withstand substantialabuse and may be made of a wide variety of materials including forexample, polypropylene plastic. The yoke 65 is formed with relativelyshort legs 66 and 67 connected integrally to a stem 68 with the legs 66and 67 having a passage in fluid communication with a passage throughthe stem 68. The cross-sectional configuration of the passage throughthe legs 66 and 67 conforms to the outer cross-sectional configurationof the bight 54. The bight 54 snugly fits within and extends through thelegs 66 and 67. An opening in the bottom of the bight 54 connects theinterior of the legs 52 and 53 with the passage through the stem 6. Ametal pin 70 is inserted in the stem 68 and extends into the bight 54.This pin 70 is formed with a tubular body 71 that is opened at eitherend. One end of the tubular body 71 is formed with an outwardly flaredlip 72. This end of the body 71 is also formed with a longitudinallyextending slot 73 which extends preferably at least one-third its lengthand in any event a distance sufiicient to permit portions of the lip 72on opposite sides of the slot 73 to be resiliently compressed toward oneanother when the pin 70 is inserted within the yoke 65. The lip 72 ispositioned within the bight 54 and has a shoulder 75 that engages theinner surface of the bight 54 thereby securely maintaining the pin 70 inengagement with the bight 54. The pin 70 is also provided with aperipheral outwardly extending flange 76 that is spaced fromthe lip 72 adistance sutficient to snugly engage the lower edge 77 of the stem 68when the lip 72 is engaged with the inner surface of the bight 54. Theportion of the tubular member 71 which projects from the flange 76beyond stem 68 is designed to engage a flexible tube 79. This flexibletube 79 which may be of any convenient length, is connected at its otherend in a conventional fashion to its chest piece. In this arrangementthe inner diameter of the pin 70 is preferably in an order of magnitudeabout twice the thickness of the wall forming the tubular member 71.

The ear tips which are preferably used in the embodiment of FIG. 12 arebest illustrated in FIGS. 16 and 17. In this arrangement the ear tip isfonned with an annular wall 80 about a passage 81. The passage 81 has afirst section 81a which is oval in cross-sectional configuration and isdimensioned to snugly fit about the ends of the ends of the legs 52 and53 in frictional engagement. This section 810 has a length which ispreferably more than half the length of the ear tip. An ad jacentsection 81b is preferably circular in cross section and forms a shoulder81c with section 81a that is adapted to engage the extreme end of thelegs 52 and 53. A section 81d continuous with section 81b may be flaredoutwardly as illustrated in FIG. 16. The outer surface 83 of the ear tipshould be shaped to conform with the outer portion of the wearer's earcanal.

The stethoscope illustrated in the preferred embodiment of FIG. 12 maybe fabricated utilizing a jig of the type illustrated in FIG. 18. In thefabrication of this stethoscope a length of tubing preferably extrudedof polypropylene and having the cross-sectional configurationillustrated in FIG. 14, is cut to a selected length as for example, 17It inches. This tubing is then heated to a temperature sutficient torender it workable.

lf'the material of which the tubing is fonned is polypropylene,

it may be preheated to a temperature of approximately 200 F. At thistemperature the tubing is softened to the extent that permits it to beflexed or bent but does not close the longitudinal hole extendingthrough it. After the tubing has been cut to a satisfactory length ayoke 65 is threaded onto this straight tubing and is centrally locatedwit respect to it. The yoke is threaded onto the tubing so that its stem68 extends perpendicularly from the major axis 56 of the tubing.

The heated tubing is then placed in a jig of the type illustrated inFIG. 18. This jig is preferably formed of metal and has two major facesand 91 lying in planes that diverge one from the other at an angle of150, channels 92, 93 and 94 are formed in the surfaces 90 and 91. Thechannels 92 and 94 are formed respectively in the surfaces 90 and 91.These channels 92 and 94 are mirror images of each and are symmetricallyarranged with respect to channel 93. Channel 93 extends longitudinallyof the jig shown in FIG. 18 and defines the adjacent edges of thesurfaces 90 and 91. The channels 92 and 94 have a cross-sectiona1configuration along their major lengths such as to receive the tubingwith the major axis 56 of the tubing in channel 92 perpendicular tosurface 90 and the major axis 56 in tube in channel 94 perpendicular tosurface 91. An enlarged portion of the channels 92, 94 is formed attheir juncture as indicated at 98 with this enlarged portion designed toreceive the yoke 65 which has previously been threaded onto the tubing.The enlargement 98 is formed with segments 99, 100 and 101 designedrespectively to receive the legs 67, 66 and stem 68 in a relatively snugfit. The channel 93 opens to end 102 of the jig and is designed topermit access through the stem 68 to the bight 54 of the tubing when itis positioned within the jig.-

The tubing is inserted into the channels of the jig of FIG. 18 with oneend of the tubing positioned at end 96 of channel 92 and the other endof the tubing positioned at end 97 of channel 94. The yoke 65 ispositioned in the enlarged portion 98 with the stem 68 lyinglongitudinally in section 101. In order to position the tubing withinthese channels of the jig the tubing is heated to approximately 200 F.At this temperature the tubing will sofien sufficiently to permit it towork and bent into the configuration of the channels 92 and 94. Afterthe tubing and yoke have been positioned in the jig the tubing issubjected to an increased amount of heat sufficient to set the tubing inthe position defined by the channels 92 and 94. If the material of thetubing is propylene the material should be heated to 300 F. andmaintained at this temperature for about 5 minutes. The temperaturehowever, should not be raised to a point that will cause the material toflow and thereby deform the tubing. The temperature should also besufficiently high to assure setting of the material in the position towhich it is initially held by the channels 92, 94.

After the tubing has been set in the position in which it is held by thejig, it is cooled. A hole is then drilled in the tubing through theopening in the stem 68 of the yoke 65 so as to complete a fluidconnection between the interior of the arms 52, 53 and the passage inthe stem 68.

While the tubing and yoke are still in the jig, the pin 70 is insertedinto the stem 68. This pin 70 is forced axially into the opening of thestem 68. When the pin 70 is forced into the stem 68 the leading end ofthe pin will be compressed as the slot 73 closes thus permitting thelips 72 to pass through the opening of the stem. The pin is forced intothe stem 68 a sufficient distance as to permit the leading end of thepin to pass though the hole that was drilled in the tubing and into theinterior of the tubing so that the lips 72 will engage the inner surfaceof the tubing. The flange 76 precisely controls the depth to which thepin may be inserted. Afier the pin has been inserted the partiallyassembled binaural is removed from the jig and is finished into astethoscope or comparable instrument by attachment of the ear tips ofthe type illustrated in FIG. 16 to the free ends of the legs 52 and 53.The tubing 79 is frictionally engaged with the projecting end of the pin71 and may have desired it be secured by a suitable means such forexample by cement. The other end of the tubing 79 may be connected to astethoscope chest piece or other instrument.

The stethoscope binaural illustrated in FIG. 12 is formed with the freeends of its legs 52 and 53 close to or substantially touching each otherwhen in a normal untensioned position. It has been found that by properselection of the material of which the tubing is formed, this shapeprovides adequate tension when the free ends are separated for placementin the wearer's ears. If desired, however, the techniques hereinillustrated may be utilized to form a stethoscope in which the legs 52and 53 crossover.

The present invention also contemplates fabricating a binaural with ayoke that is attached after the binaural has been shaped in the manneras previously described. In such an arrangement the yoke is formed ofmating pairs which are attached to the bight of the binaural tube afterthe tube has been shaped. The yoke may comprise a male 110 and a femalehalf 112 shown respectively in FIGS. 19 and 21. These halves eachprovide arcuately curved legs 113 and 114 having cross-sectionalconfigurations which are semicircular. The opposite longitudinal edgesof the leg 113 are provided with a longitudinally extending bead 115illustrated in large form in FIG. 23. The opposite longitudinal edges ofthe legs 114 are formed with a female channel or recess 116 that isdesigned to mate with the bead 115. The two halves 110 and 112 may besnapped over the bight 54 of the tubular member and may be suitablysecured together by cement or other means. A stem or tube 118 projectsoutwardly from and secured at one end within an opening formed bycutaway portions in the opposite legs I13 and 114.

A still further modification of the present invention is illustrated inFIG. 24. In this arrangement the binaural is formed in a two-piececonstruction with one of the pieces illustrated in FIG. 24. The piecenot shown is a mating piece designed to mate with the piece shown inFIG. 24 along its entire length to form a complete binaural. The pieceshown in FIG. 24 has leg segments 154 and 155 connected by a bightsegment 156 car tip segments I57 and 158 are integrally formed at theends of the segments I54 and 155 respectively. A stem segment 160 isconnected to and integrally formed with bight section 156. Thecross-sectional configurations of the various sections illustrated inFIG. 24 are shown respectively in FIGS. 24a to 241. It will be notedthat the cross-sectional configurations illustrated in FIGS. 24a, b, c,d, e all have projecting beads or ribs 170 along one or both sides asillustrated. When a mating half is placed in facing relation and the twomating halves are subject to a conventional ultrasonic-sealing process,the beads 170 will fuse into the opposite surface and provide apermanent interengagement. The beads are formed only on onehalf of theedges of the component illustrated in FIG. 24 leaving smooth the legsegment I55 and one half of the stem segment I60 thus providing a smoothsurface against which the bead 170 may rest when they are placed infacing engagement for ultrasonic sealing.

After the two halves are joined as described, the legs which are formedfrom the leg segments 154, 155 are bent so that they lie in planes thatintersect at an angle of 150". This may be effected by heating themembers which have been joined ultrasonically to a temperaturesufficient to permit the binaural to be worked but not high enough tocause deformation. And if polypropylene is used as the material, atemperature in the order of 300 F. should be satisfactory.

The embodiment illustrated in FIG. 24 may also be made in severaladditional segments wherein the leg segments I54 and 155 are formedseparately from and independently of the bight. The bight in turn may beintegrally formed as a yoke adapted to receive the assembled legs 154and 155.

In a further modification of this invention a tubing is formed andshaped in a jig of the type described in FIG. 18 except that no yoke isattached to the tubing before its shaping. Thereafter a pin is insertedthrough the wall of the tubing extending downwardly from the bight. Thetube is then dipped in a hot dip of a suitable plastic whereby the bightportion of the tube and the inserted pin are coated with the moltenplastic to form an integral yoke. The pin is thereafter removed from thestem of the yoke. yoke. A suitable material for such dip may comprisethe material which hardens upon cooling into a flexible and preferablyresilient material. Suitable rubber latex and resins may be used.

What is claimed is:

l. A binaural construction formed of an elongated tubular homogenousplastic mass having a cross-sectional configuration wherein onecross-sectional axis is greater than a corresponding cross-sectionalaxis normal thereto, said binaural having a pair of rigid legs and aninterconnecting bight section continuous and integral with said legs,means for resiliently tensioning said legs toward a normal untensionedposition against deforming forces with said last-mentioned means formedat least in part by the characteristics of said mass, a tubular stem,and means securing said stem to said bight with the passages defined bysaid tubular mass and said tubular stem in fluid communication, saidsecuring means including a tubular body with one wall defining saidtubular body coaxial with and engaging an annular surface at one end ofsaid tubular stem, said tubular body having an end projecting from saidone end of said tubular stem into engagement with said bight with aportion of said one end of said tubular body extending angularly fromthe axis thereof into locking relation with said bight.

2. A binaural construction formed of an elongated tubular homogenousplastic mass having a cross-sectional configuration wherein onecross-sectional axis is greater than a corresponding cross-sectionalaxis normal thereto, said binaural having a pair of rigid legs and aninterconnecting bight section continuous and integral with said legs,means for resiliently tensioning said legs toward a normal untensionedposition against deforming forces with said last mentioned means atleast in part by the characteristics of said mass, wherein a wall formedby said tubular cross section is nonuniform in thickness, and at leastin part defines said means for resiliently tensioning said legs, atubular stem, and means securing said stem to said bight with thepassages defined by said tubular mass and said tubular stem in fluidcommunication.

3. A binaural as set forth in claim 2 wherein said wall is continuousalong its length except for a portion in said bight wherein a holeextends therethrough in a direction away from the direction of saidlegs.

4. A binaural set forth in claim 3 wherein the thicker portions of saidwalls extend in directions substantially normal to a plane passingthrough both of said legs of said binaural.

5. A binaural as set forth in claim 4 wherein the ear tube ends of saidbinaurals extend at an angle of substantially 15 from a major plane,said major plane being defined as a plane of a flat surface upon whichsaid binaural rests when laid upon said surface with both legs incontact therewith.

6. A binaural as set forth in claim wherein said means securing saidstem includes, a yoke of generally a T-shaped configuration with thecrossmember of the T channelled to conform and engage said bight oversaid hole, and the stem of said T-shaped configuration is tubular.

7. A binaural as set forth in claim 6 wherein the wall thickness of saidcrossmember tapers from thick to thin in a direction away from saidstem.

8. A binaural construction formed of a pair of nonparallel, plastic legsinterconnected by a plastic bight and a flexible tube operativelyengaged with said bight, said legs and bight comprising an elongated,integral, continuous, tubular, homogenous, rigid mass having anonuniform, cross-sectional shape and a composition resilientlyresistive to deforming forces, said flexible tube formed of anelongated, flexible, tubular member with means interconnecting theinterior of said flexible tube and bight, and one of said legs and anadjacent portion of said bight lying substantially in a planeintersecting at an angle a second plane with said other leg and portionof said bight adjacent thereto lying substantially in said second plane.

9. A binaural construction as set forth in claim 8 wherein said meansinterconnecting said flexible tube and bight is fonned of material morerigid than said flexible tube and bight.

10. A binaural comprising a U-shaped, tubular plastic member an aflexible tube extending from and in fluid communication with saidU-shaped member, and said U-shaped tubular member having a bight portionformed of a rigid, homogeneous mass having resilient characteristicsexhibiting springlike action such as to resist deflection of the legs ofsaid U-shape from a selected nonparallel position by deflecting forces,said tubular member having at least one surface which is noncircular incross section with two orthogonally related nonequal dimensions, thelarger of the two dimensions lying in a planesubstantially normal to aplane containing the legs of said U-shaped member, whereby said binauralmay be secured with said legs exerting pressure on opposite sides of auser's head, and means connecting said flexible tube to said U- shapedtubular member.

ll. A binaural as set forth in claim 10 wherein said tubular member isformed of an integral, continuous single piece of material integrallyand continuously formed.

12. A binaural as set forth in claim 11 wherein said bight portion andlegs are formed of a continuous single member having a tubular passagewith a noncircular cross section.

13. A binaural as set forth in claim 10 wherein said legs have an outersurface with a noncircular cross section.

14. A binaural as set forth in claim 10 wherein said bight and said legsare formed of a continuous length of plastic material having anoncircular cross section, and said means connecting said flexible tubeto said U-shaped tubular member comprises a yoke having two yoke legsand a yoke stem with said yoke legs interengaging said, tubular memberand said yoke stem interengaging said flexible tube 15. A binaural asset forth in claim 14 wherein said yoke is formed of a material ofgreater rigidity and resilience than said tubular member.

16. A binaural as set forth in claim 10 wherein the outer surface ofsaid tubularmember is oval in cross-sectional configuration.

17. A binaural as set forth in claim 16 having car tips coaxiallysecured to the ends of said legs of said tubular member and having anopening in facing engagement with the ends of said legs, said openingsof said car tips having an oval cross section.

18. A binaural as set forth in claim 10 wherein said means connectingsaid flexible tube to said U-shaped tubular member comprises a tubularinsert having one end engaging said flexible tube and the other endextending into said bight portion.

19. A binaural as set forth in claim 18 wherein said other end of saidtubular insert is formed with an outwardly flared lip eng g the innerwall of said bight.

20. manure] as set forth in claim 19 wherein said insert is formed ofmetal and said insert extends into and is coaxial with said stem.

21. A binaural construction formed of a pair of nonparallel, plasticlegs interconnected by a plastic bight and a tubular stem extendingangularly from said bight, said legs and bight comprising an elongated,integral, continuous, tubular, homogeneous, rigid mass having anonuniform, cross-see tional shape and a composition resilientlyresistive to deforming forces, said stem fonned of an elongated,flexible, tubular member with means interconnecting the interior of saidstem and bight, said tubular member having an outer surface that is ovalin cross-sectional configuration and an inner surface that is circularin cross-sectional configuration, and one of said legs and an adjacentportion of said bight lying substantially in a plane intersecting at anangle a second plane with said other leg and portion of said bightadjacent thereto lying substantially in said second plane.

22. A binaural as set forth in claim 21 wherein the major axis of saidoval configuration extends angularly from the major plane of saidbinaural.

1. A binaural construction formed of an elongated tubular homogenousplastic mass having a cross-sectional configuration wherein onecross-sectional axis is greater than a corresponding cross-sectionalaxis normal thereto, said binaural having a pair of rigid legs and aninterconnecting bight section continuous and integral with said legs,means for resiliently tensioning said legs toward a normal untensionedposition against deforming forces with said last-mentioned means formedat least in part by the characteristics of said mass, a tubular stem,and means securing said stem to said bight with the passages defined bysaid tubular mass and said tubular stem in fluid communication, saidsecuring means including a tubular body with one wall defining saidtubular body coaxial with and engaging an annular surface at one end ofsaid tubular stem, said tubular body having an end projecting from saidone end of said tubular stem into engagement with said bight with aportion of said one end of said tubular body extending angularly fromthe axis thereof into locking relation with said bight.
 2. A binauralconstruction formed of an elongated tubular homogenous plastic masshaving a cross-sectional configuration wherein one cross-sectional axisis greater than a corresponding cross-sectional axis normal thereto,said binaural having a pair of rigid legs and an interconnecting bightsection continuous and integral with said legs, means for resilientlytensioning said legs toward a normal untensioned position againstdeforming forces with said last mentioned means formed at least in partby the characteristics of said mass, wherein a wall formed by saidtubular cross section is nonuniform in thickness, and at least in partdefines said means for resiliently tensioning said legs, a tubular stem,and means securing said stem to said bight with the passages defined bysaid tubular mass and said tubular stem in fluid communication.
 3. Abinaural as set forth in claim 2 wherein said wall is continUous alongits length except for a portion in said bight wherein a hole extendstherethrough in a direction away from the direction of said legs.
 4. Abinaural set forth in claim 3 wherein the thicker portions of said wallsextend in directions substantially normal to a plane passing throughboth of said legs of said binaural.
 5. A binaural as set forth in claim4 wherein the ear tube ends of said binaurals extend at an angle ofsubstantially 15* from a major plane, said major plane being defined asa plane of a flat surface upon which said binaural rests when laid uponsaid surface with both legs in contact therewith.
 6. A binaural as setforth in claim 5 wherein said means securing said stem includes, a yokeof generally a T-shaped configuration with the crossmember of the Tchannelled to conform and engage said bight over said hole, and the stemof said T-shaped configuration is tubular.
 7. A binaural as set forth inclaim 6 wherein the wall thickness of said crossmember tapers from thickto thin in a direction away from said stem.
 8. A binaural constructionformed of a pair of nonparallel, plastic legs interconnected by aplastic bight and a flexible tube operatively engaged with said bight,said legs and bight comprising an elongated, integral, continuous,tubular, homogenous, rigid mass having a nonuniform, cross-sectionalshape and a composition resiliently resistive to deforming forces, saidflexible tube formed of an elongated, flexible, tubular member withmeans interconnecting the interior of said flexible tube and bight, andone of said legs and an adjacent portion of said bight lyingsubstantially in a plane intersecting at an angle a second plane withsaid other leg and portion of said bight adjacent thereto lyingsubstantially in said second plane.
 9. A binaural construction as setforth in claim 8 wherein said means interconnecting said flexible tubeand bight is formed of material more rigid than said flexible tube andbight.
 10. A binaural comprising a U-shaped, tubular plastic member anda flexible tube extending from and in fluid communication with saidU-shaped member, and said U-shaped tubular member having a bight portionformed of a rigid, homogeneous mass having resilient characteristicsexhibiting springlike action such as to resist deflection of the legs ofsaid U-shape from a selected nonparallel position by deflecting forces,said tubular member having at least one surface which is noncircular incross section with two orthogonally related nonequal dimensions, thelarger of the two dimensions lying in a plane substantially normal to aplane containing the legs of said U-shaped member, whereby said binauralmay be secured with said legs exerting pressure on opposite sides of auser''s head, and means connecting said flexible tube to said U-shapedtubular member.
 11. A binaural as set forth in claim 10 wherein saidtubular member is formed of an integral, continuous single piece ofmaterial integrally and continuously formed.
 12. A binaural as set forthin claim 11 wherein said bight portion and legs are formed of acontinuous single member having a tubular passage with a noncircularcross section.
 13. A binaural as set forth in claim 10 wherein said legshave an outer surface with a noncircular cross section.
 14. A binauralas set forth in claim 10 wherein said bight and said legs are formed ofa continuous length of plastic material having a noncircular crosssection, and said means connecting said flexible tube to said U-shapedtubular member comprises a yoke having two yoke legs and a yoke stemwith said yoke legs interengaging said, tubular member and said yokestem interengaging said flexible tube.
 15. A binaural as set forth inclaim 14 wherein said yoke is formed of a material of greater rigidityand resilience than said tubular member.
 16. A binaural as set forth inclaim 10 wherein the outer surface of said tubular member is oval incross-sectional configuration.
 17. A binaural as set forth in claim 16having ear tips coaxially secured to the ends of said legs of saidtubular member and having an opening in facing engagement with the endsof said legs, said openings of said ear tips having an oval crosssection.
 18. A binaural as set forth in claim 10 wherein said meansconnecting said flexible tube to said U-shaped, tubular member comprisesa tubular insert having one end engaging said flexible tube and theother end extending into said bight portion.
 19. A binaural as set forthin claim 18 wherein said other end of said tubular insert is formed withan outwardly flared lip engaging the inner wall of said bight.
 20. Abinaural as set forth in claim 19 wherein said insert is formed of metaland said insert extends into and is coaxial with said stem.
 21. Abinaural construction formed of a pair of nonparallel, plastic legsinterconnected by a plastic bight and a tubular stem extending angularlyfrom said bight, said legs and bight comprising an elongated, integral,continuous, tubular, homogeneous, rigid mass having a nonuniform,cross-sectional shape and a composition resiliently resistive todeforming forces, said stem formed of an elongated, flexible, tubularmember with means interconnecting the interior of said stem and bight,said tubular member having an outer surface that is oval incross-sectional configuration and an inner surface that is circular incross-sectional configuration, and one of said legs and an adjacentportion of said bight lying substantially in a plane intersecting at anangle a second plane with said other leg and portion of said bightadjacent thereto lying substantially in said second plane.
 22. Abinaural as set forth in claim 21 wherein the major axis of said ovalconfiguration extends angularly from the major plane of said binaural.